Circuit breakers of this type can be configured as motor circuit breakers or as automatic circuit breakers that are employed to switch a load on and off and that have a protective function by separating or interrupting the load in case of an electrical fault. Electrical faults can be short circuits, overcurrents or else undervoltages. Examples of typical circuit breakers are also residual current circuit breakers (for instance, German patent application DE 4106652 A1) which, however, cannot be utilized to switch loads on and off.
An example of a circuit breaker of the generic type is presented in German patent application DE 198 36 549 A1. The tripping unit can be of the conventional type, for instance, like the one described in GB 1,558,785. Here, the magnetic mechanism consists of a solenoid armature which can move linearly in a solenoid coil and which is configured as a tripping tappet that can be moved towards a permanent magnet against the force of a pressure spring by means of which it is held in place when the solenoid coil is de-energized.
In the case of many circuit breakers, the space available for the installation of a tripping unit is small. In view of the low voltage level, this is an economical solution for use in the automotive sector (German patent specification DE 197 41 919 C1). However, for low-voltage applications, higher requirements in terms of insulation and higher switching capacities have to be achieved.